1. Field of Invention
The present invention relates to a gasket for a vehicle. More particularly, the present invention relates a gasket for a vehicle provided to an exhaust manifold.
2. Description of Related Art
Generally, engine output per cycle can be increased when pressure of intake air flowing into a cylinder of an engine is increased to higher than atmospheric pressure and an air amount in the cylinder is increased. This is called supercharging. Mechanical supercharging deteriorates thermal efficiency even though crankshaft power is increased since output of a crankshaft is used for compressing the intake air.
In order to solve the problem, a turbocharger has been developed. According to the turbocharger, a compressor fixedly connected with an exhaust turbine feeds air into the cylinder when the exhaust turbine is operated by energy from exhaust gas. Therefore, engine output is improved. The turbocharger is widely used with diesel engines where a knocking problem does not generally occur as opposed to a gasoline engine where knocking occurs if the pressure in the cylinder is excessively increased by supercharging.
In detail, in the turbocharger, a turbine wheel that recovers exhaust energy and a compressor wheel that delivers compressed air to the cylinder are disposed on respective ends of the same shaft, and a housing for leading flow of the exhaust gas and the air covers each wheel. Particularly, the turbine housing is divided into a single scroll type having one exhaust gas passage and a twin scroll type having two exhaust gas passages divided by a partition. The twin scroll type prevents exhaust interference of the engine and efficiently uses a pulse effect of the exhaust, and thus rotation efficiency of the turbine wheel can be improved.
Meanwhile, the turbocharger is connected with an exhaust manifold, and a gasket is provided on a surface where the exhaust manifold is assembled with the cylinder head of the engine. In addition, a shape of the gasket corresponds to a shape of the surface where the exhaust manifold and the cylinder head are coupled with each other. Further, the gasket seals by using elastic force of a bead in which a stainless steel material of a thin plate is processed by embossing molding.
However, in the turbocharger using the twin scroll type, a part of the exhaust manifold has a large cross-section so as to secure a space where the twin scroll is formed. In addition, a part of the exhaust manifold having the large cross-section cannot be directly engaged with the cylinder head. In other words, a disengaged portion of the gasket is formed. Thus, at the disengaged portion, leakage of exhaust gas may occur since an engaging force between the cylinder head and the exhaust manifold deteriorates.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.